Two-stage Treatment Research Articles

Highly selective Mg2+/Li+ separation membranes prepared by surface grafting of a novel quaternary ammonium bromide

The efficient separation of Mg2+ and Li+ is the crucial step in the process of extracting lithium from salt lake brine. Nanofiltration (NF) membranes exhibit promising application potential in Mg2+/Li+ separation but the Mg2+/Li+ selectively of negatively charged NF membranes prepared by conventional interfacial polymerization process is far from desirable. In this study, a novel positively charged quaternary ammonium bromide, 3-bromopropyl trimethylammonium bromide (BTAB), is grafted on the polyethyleneimine (PEI)/trimesoyl chloride (TMC) NF membrane surface. This is achieved by a chemical reaction known as nucleophilic substitution, which involves the replacement of a bromine atom (-Br) with an amine group. Owing to the enhanced Donnan effects, the BTAB-modified NF membranes exhibit a MgCl2 rejection of up to 99.2 %, while maintaining a water flux of approximately 50 LMH under 5 bar. Meanwhile, the LiCl rejection is only ∼ 30 %. The Mg2+/Li+ selectively of the BTAB-modified NF membranes reaches 95.9 when filtrating a simulated brine with a Mg2+/Li+ ratio of 20 (2000 ppm MgCl2 and LiCl mixture), which is a twofold improvement compared with the pristine NF membranes. The working stability of the BTAB-modified NF membranes is confirmed by a 50-h continuous operation process. A two-stage NF treatment is conducted using a simulated East Taijinar salt lake brine, achieving Li2CO3 powder with a purity level of 99.4 %. The nucleophilic substitution reaction between -Br and the amine groups offers a good reference for the surface functionalization of NF membranes.

Experience of Two-Stage Treatment of Rectal Fistulas Using Low-Thrombin Fibrin Glue “Kriofit”

Experience of Two-Stage Treatment of Rectal Fistulas Using Low-Thrombin Fibrin Glue “Kriofit”

Huge renal angiomyolipoma

Renal angiomyolipoma (AML) is a rare solid benign tumor composed of varying amounts of mature adipose tissue, smooth muscle, and thick-walled vessels. This article presents a clinical observation and immediate results of a two-stage treatment of giant renal AML (preliminary superselective embolization with further partial nephrectomy) in a 58-year-old woman.

Combining fungal bioremediation and ozonation for rinse wastewater treatment

In this work, agricultural rinse wastewater, which is produced during the cleaning of agricultural equipment and constitutes a major source of pesticides, was treated by fungal bioremediation and ozonation, both individually and combined in a two-stage treatment train. Three major pesticides (thiacloprid, chlortoluron, and pyrimethanil) were detected in rinse wastewater, with a total concentration of 38.47 mg C L−1. Comparing both technologies, ozonation in a stirred reactor achieved complete removal of these pesticides (720 min) while proving to be a more effective approach for reducing colour, organic matter, and bacteria. However, this technique produced transformation products and increased toxicity. In contrast, fungal bioremediation in a rotating drum bioreactor attenuated toxicity levels and did not produce such metabolites, but only removed approximately 50 % of target pesticide - hydraulic retention time (HRT) of 5 days - and obtained worse results for most of the general quality parameters studied. This work also includes a preliminary economic assessment of both technologies, revealing that fungal bioremediation was 2 times more cost-effective than ozonation. The treatment train, consisting of a first stage of fungal bioremediation followed by ozonation, was found to be a promising approach as it synergistically combines the advantages of both treatments, achieving high removals of pesticides (up to 100 %) and transformation products, while reducing operating costs and producing a biodegradable effluent. This is the first time that fungal bioremediation and ozonation technologies have been compared and combined in a treatment train to deal with pesticides in agricultural rinse wastewater.

Does fertility intention affect household consumption? Evidence from China

ABSTRACTChina is grappling with steep demographic challenges: low fertility rates, a shrinking labour force, and a rising old-age dependency ratio. Combined with its perennially high savings rates, these can stifle consumption spending and overall economic growth. This paper is devoted to analysing the effects of fertility intention, the precursor to fertility rates, on the average propensity to consume in China. Using the two-stage endogenous treatment regression model to account for the endogeneity of fertility intention, we analyse the 2019 and 2021 Chinese Social Survey (CSS) data collected by the Chinese Academy of Social Sciences. The results show that those intending to have more children spend less as a proportion of their income. Furthermore, individuals’ intentions to have more children are negatively associated with age and household size and positively associated with education. Getting remarried and fertility intention are also positively related. Disaggregated analysis shows that the effects of fertility intention on the average propensity to consume vary across household income quartiles, between males and females, urban and rural residents, and households of different sizes. Policies that simultaneously stimulate spending and incentivize having more children should be considered.

Microstructural and mechanical properties of additive manufactured 2319 aluminum alloy annular-shaped components: As-built and multistage heat treatment

A novel multistage aging heat-treatment method was applied to investigate the microstructural evolution and properties of an additive-manufactured 2319 aluminum alloy. The microstructure and mechanical properties were analyzed, and the results revealed that the as-built annular-shaped components were characterized by an alternating distribution of thin equiaxed crystals, dendrites, and coarse columnar crystals. The microstructure occurs recrystallization and the average grain size decreased after the two-stage aging treatment. The maximum texture strength in the selected area increased after the two-stage aging treatment, and the angle grain boundaries were evenly distributed. Solid solution plus aging could significantly improve ultimate tensile strength and hardness. The tensile fracture morphology was typical of ductile fracture. Two-stage aging exhibited a higher corrosion resistance.

Effective treatment of leachate concentrate from waste incineration plant by combination of coagulation and direct contact evaporation

In order to verify that coagulation as pre-treatment can reduce the temperature of the hot air used for direct contact evaporating the leachate concentrate (LC) and low-grade waste heat such as exhaust steam in the waste incineration plant can be used to evaporate the LC. The supernatants after coagulation using polymerized ferrous sulfate (PFS), polymeric-aluminum (PAC), polymeric silicate aluminum ferric (PSAF) and poly-aluminum ferric chloride (PAFC) as coagulants were further treated in a lab-scale direct contact evaporation system. The results showed that the best performance with removal efficiencies of COD and NH3–N of 58.70% and 29.09% was achieved after coagulation when PAFC dosage = 15 g/L, PAM dosage = 30 mg/L and initial pH of supernatant = 6. After coagulation, a large amount of the fulvic-like acid and aromatic heterocyclic compounds were removed and the degree of complexity and aromaticity of organics decreased. After direct contact evaporation, using PAFC as coagulant still was the best selection due to its lowest concentrations of COD and NH3–N (22 mg/L and 1.02 mg/L) in the condensate produced by this two-stage treatment when initial pH of supernatant was 6 during evaporation and the condensate produced by this two-stage treatment met the water quality standard for using as supplying water for circulating cooling water system when temperature of hot air used for heating LC was at low temperature (250 °C). The fulvic-like acid and aromatic heterocyclic compounds in the condensate continuously reduced. Phenol, adamantane, 1-isocyanato, phthalic anhydrid, tri(2-chloroethyl) phosphat, Heptadecane, 2-methyl, ginsenol and Octadecane, 2-methyl- in the condensate obviously decreased. The effect of four coagulants as pretreatment on reducing the temperature of hot air used for evaporating LC was ranked as PAFC > PFS > PAC > PSAF. PSAF was not recommended due to the large amount of NH3–N produced when using PSAF to treat the LC.

LARGE INTESTINES COMPLICATED DIVERTICULITIS MODERN TREATMENT TACTICS USING VIDEOENDOSCOPIC EQUIPMENT

Abstract. Colonic diverticular disease (CDD) is an important problem in abdominal surgery for the majority countries of the world. The incidence of CDD is, unfortunately, progressing. The CDD relevance is determined by medical and economic aspects taking into account the disease frequent cases in working age persons. The tactics of CDD treatment is considered to be traditional and is determined according to the generally accepted modifi ed disease classifi cation according to E. J. Hinchey. Using daily the tactics of a personalized approach to patients we agree with the opinion of our colleagues and consider the choice of sigmoid colon acute diverticulitis and its complications optimal method of diagnosis and surgical treatment to be still arguing. Having considerable experience and treating patients with CDD for a long time, we try to use mostly the laparoscopic approach in surgical tactics the eff ectiveness of which we intend to summarize.The purpose. To determine the eff ectiveness of the laparoscopic method of surgical treatment of patients with CDD complicated clinical manifestation. Research material and methods. The treatment of 221 patients with 263 surgical interventions due to CDD and its complications was analyzed. CDD complicated forms were diagnosed in 186 (84.5 %) patients. 164 (62.4 %) operations were performed urgently, 102 (61.7 %) of which were performed using videoendoscopic equipment, 62 (38.3 %) were performed using the traditional open method. Open operations performed under urgent indications. Special attention was attracted to patients with bleeding as CDD complication. 9 patients (in 6 with initial intestinal bleeding and in 3 with CDD complicated by profuse bleeding) underwent operative treatment. All patients were treated in one stage.Results and their discussion. According to planned indications, 26 laparoscopic and 31 open resections of the large intestine were performed due to CDD. The source of infl ammation was localized in the sigmoid colon in all patients. Infl ammation of one diverticulum occurred in 56 (98.4 %) cases, two diverticulies – in 1 (1.6 %) observation. 49 patients were treated in 2 stages. Perforation of the diverticulum wall was detected in 79 (51.6 %) patients. The duration of operative treatment of patients with complicated CDD using videoendoscopic equipment was 73.4±6.2 min. The index of bed days duration with laparoscopic operations was 6.1±0.7. The patients’ stay in the hospital after scheduled videoendoscopic operations was 6.3±1.6 days. From 9 patients with bleeding in the absence of conservative therapy effi cacy and under the condition of the patient’s stable condition, 4 patients underwent laparoscopic left-sided hemicolectomy. Open surgical interventions were performed in 5 patients, mostly elderly and with severe concomitant pathology.Conclusions. In case of patients with a CDD complicated course treatment we consider a two-stage treatment preferable, when the second stage (left-sided hemicolectomy) is performed in a planned manner within 9 days to 6 months after the operation for urgent indications. Patients with complicated CDD operative treatment is better to be performed with the use of videoendoscopic equipment. It is better to perform repeated planned radical operations for CDD laparoscopically, which is evidenced by a lower number of complications. The use of laparoscopic technologies in case of colonic bleeding treatment as CDD complication is a promising direction in abdominal surgery and requires its e ffi ciency further study.

A case of successful fertility of a patient with bilateral varicocele on the background of May–Thurner syndrome by combining transscrotal varicocelectomy with X-ray endovascular correction of iliac vessel compression

Arteriovenous conflicts of the ileocecal segment are a frequent cause of recurrent and bilateral varicocele. Insufficient and untimely diagnosis of varicocele causes in this group of patients leads to multiple repeated surgical interventions due to recurrence. This paper presents a clinical case of successful fertility of a 30-year-old patient with bilateral varicocele and testicular hypotrophy on the background of MeyThurner syndrome by two-stage surgical treatment including transsclerotal ligation of testicular veins, angioplasty and stenting of the left common iliac vein.

Dual modification of natural rubber/halloysite nanotubes composites by silane and maleated natural rubber

As the performance of natural rubber (NR) and halloysite nanotube (HNT) composites is uncertain due to low compatibility between the materials, malleated natural rubber (MNR) is then used as a compatibilizer to encourage filler–rubber compatibility. However, the properties of these composites remain unsatisfactory, and the treatment of HNT requires further improvement. Therefore, this study introduced acid treatment and silane coupling agents to increase the interactions between NR and HNT. Besides, this study also introduced the methods of compounding the rubber composites, either with single-stage or two-stage treatments. The application of a two-stage treatment to acid-treated HNT has given tensile strength a 26.5% improvement. Two-stage treatment enabled better silanization, while acid-treated HNT provided effective silanols for such interactions. The use of silane with acid-treated HNT was found to enhance the tensile strength, modulus, and tear strength of the composites, which was clearly due to better filler–rubber interactions. The Payne effect, which decreased up to 64.03% after applying a two-stage treatment, served as further confirmation of better filler–rrubber interactions. This conclusively proved that modifying both the rubber matrix and HNT enhances the performance of NR/HNT composites.

Influence of multi-stage processing and mechano-chemical treatments on the hydration and microstructure properties of recycled aggregate concrete

On account of the shortage of naturally occurring coarse aggregate, recycled aggregate (RA) made from crushed concrete debris is now used in the construction industry. With this rise in the utilisation of recycled aggregate in the construction sector, there has been extensive research into ways to improve its quality. The significant fraction of mortar remains that are left on the RA surface is the primary factor that affects its quality. Concrete made from RA loses strength and mechanical performance due to the attached mortar's increased porosity and water absorption values and the frailer transition region between the new mortar and aggregates. In order to minimise the old cement fractions and increase the quality, this paper studies the effect of concrete incorporating multi-stage processed RA from demolished concrete waste, followed by treatment with mechanical abrasion and sodium silicate immersion. The recycled aggregates were produced through multi-stage jaw crushing, followed by utilising natural aggregate, recycled aggregate, and recycled aggregate obtained after mechanical abrasion, followed by sodium silicate treatment for concrete mix design at various substitution percentages as coarse aggregates. The experimental investigation further progresses with the evaluation of mechanical and durability properties of concrete mixes, which is additionally followed by microstructural studies such as scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Thermogravimetry-differential thermal analysis (TG-DTA). The outcomes demonstrate that two-stage treatment, such as mechanical abrasion followed by sodium silicate immersion, yields superior-quality RA. Recycled aggregate concrete (RAC) made with these treated aggregates illustrated an increase in workability and density with respect to an untreated RAC mix. Furthermore, comparable strengths in compression, flexure, and tension are found in treated RAC mixes, particularly at 35% replacement levels, with respect to concrete mixes comprised of natural aggregates. A similar trend is detected in the chloride penetration tests and water sorptivity tests. In addition, the microstructural investigation confirmed the formation of additional calcium silicate hydrate for treated RAC mixes, particularly for the 35% substituted RA mix. On the basis of the results, it is suggested that multi-stage jaw crushing followed by treatment through mechanical abrasion and sodium silicate can potentially enhance the mechanical, microstructural, and durability performance of RAC.

A comparative life cycle assessment on recycled concrete aggregates modified by accelerated carbonation treatment and traditional methods

Recycling of construction and demolition wastes contributes to achieve carbon summit and carbon neutrality early in the construction industry. Accelerated carbonation is a promising new technology for enhancing the properties of recycled concrete aggregates (RCAs) as well as mitigating global warming. This study performed a comparative life cycle assessment on RCAs modified by accelerated carbonation treatment and traditional methods. The effect of different treatment methods on environmental impacts of concrete was evaluated. The key contributors of environmental impacts for concrete incorporating carbonated RCAs were identified. Moreover, a sensitivity analysis on the transport distance of concrete incorporating carbonated RCAs was conducted. Results demonstrated that incorporating carbonated RCAs could significantly reduce the energy demand, environmental impacts and environmental cost compared with natural aggregate concrete. Accelerated carbonation treatment exhibited greater potential than the normal two-stage crushing and heating treatment in mitigating environmental burden, especially for the global warming potential. Cement production and transportation were the primary contributors to environmental impacts of concrete incorporating carbonated RCAs. Sensitivity analysis indicated incorporating carbonated RCAs as alternatives of natural aggregates contributes to lower the environmental impacts of concrete when the natural aggregates are far from urban areas while the recycling center is near the city.

Microstructural and textural gradients in SLM-manufactured AlSi10Mg after low-draught cold-rolling and heat treatment

Additively manufactured AlSi10Mg is often subject to a two-stage heat treatment, namely solid solution treatment followed by artificial aging, to achieve optimal properties. Before such heat treatments, slight surface plastic deformation may be applied to modify the surface quality and properties. However, gradients in microstructure and texture near the surface introduced by the plastic deformation may cause undesired microstructural and textural evolutions during subsequent heat treatment. In this work, we introduce plastic deformation in the surface layer in an SLM-manufactured AlSi10Mg sample by relatively low-draught cold rolling and we investigate the through-thickness variations in microstructure and texture in the deformed state and after heat treatment. The SLM-manufactured AlSi10Mg sample has a fine-scale microstructure and a weak texture, and is rather thermally stable during subsequent heat treatments. Applying 10% low-draught cold rolling to the SLM-manufactured AlSi10Mg sample is found to introduce a near Goss texture in the surface layer, while little change is observed in the center layer. After subsequent solution treatment and aging, abnormal grain growth occurred in the surface layer resulting in remarkable through thickness gradients in microstructure and texture.

Organic binding iron formation and its mitigation in cation exchange resin assisted anaerobic digestion of chemically enhanced primary sedimentation sludge

Fe based chemically enhanced primary sedimentation (CEPS) is an effective method of capturing the colloidal particles and inorganic phosphorous (P) from wastewater but also produces Fe-CEPS sludge. Anaerobic digestion is recommended to treat the sludge for energy and phosphorus recovery. However, the aggregated sludge flocs caused by the coagulation limited sludge hydrolysis and P release during anaerobic digestion process. In this study, cation exchange resin (CER) was employed during anaerobic digestion of Fe-CEPS sludge with aims of prompting P release and carbon recovery. CER addition effectively dispersed the sludge flocs. However, the greater dispersion of sludge flocs could not translate to higher sludge hydrolysis. The maximum hydrolysis and acidification achieved at lower CER dosage of 0.5 g CER/g TS. It was observed that the extents of sludge hydrolysis and acidification had a strongly negative correlation with the organic binding iron (OBI) concentration. The presence of CER during anaerobic digestion favored Fe(III) reduction to Fe(II), and then further induced iron phase transformation, leading to the OBI formation from the released organic matters. Meanwhile, higher CER dosage resulted in higher P release efficiency and the maximum efficiency at 4 g CER/g TS was four times than that of the control. The reduction of BD-P, NaOH-P and HCl-P in solid phase contributed most P release into the supernatant. A new two-stage treatment process was further developed to immigrate the OBI formation and improve the carbon recovery efficiency. Through this process, approximately 45% of P was released, and 63% of carbon was recovered as methane from Fe-CEPS sludge via CER pretreatment.

Modern technologies in treatment of pilonidal sinus

Objective. Improvement of treatment results and reduction of the number of relapses in patients with pilonidal disease, by developing and substantiating a two-stage treatment method (with the use of laser treatment and subsequent radical surgical intervention). Materials and Methods. A prospective analysis of the treatment results of 76 patients at the clinical sites of the Rostov State Medical University was carried out. The patients were divided into three clinical observation groups: In Group I (the main group, 26 patients), two-stage treatment was carried out according to the original technique (patent № 2770283). In Group II (the first control group, 28 observations), we used the "сleft lift" procedure according to the Bascom authentic method Bascom II method modified by Karydakis). In Group III (the second control group, 22 observations), the pilonidal sinus was dissected with the traditional technique of plastic surgery of the sacrococcygeal region with "deaf" sutures along the gluteal cleft. Results. Analysis of the results showed that the postoperative period was smoother in Group I patients due to the smaller size of the surgical defect and the radical surgical stage in the absence of local inflammatory tissue reaction. There were no significant infiltrative-inflammatory complications in the patients operated on according to the original two-stage method. There were no recurrences during the one-year outpatient follow-up period. According to the VAS score, postoperative pain syndrome was significantly lower in Group I patients. The duration of hospitalization and period of disability were reduced in the patients of the main group in comparison with the same parameters in the control groups. The indicated pharmaco-economic effect in comparison with the traditional methods of surgical treatment was obtained due to early healing of the operative wounds with a smaller inflammatory reaction of the soft tissues and a reduced risk of suppurative complications. Conclusion. The developed method of two-stage surgical treatment of pilonidal sinus helps to increase the effectiveness of radical treatment, reduce the number of relapses and complications, and reduce the duration of patients' disability. The described efficacy of the technology is achieved with early healing and stable qualitative aesthetic result.

Microstructure and mechanical properties of 0.2C-3.9Al-1.12Mn-0.3Mo δ-TRIP steel as a function of isothermal bainitic transformation temperature

The present investigation employed a two-stage heat treatment on a δ-transformation-induced plasticity (TRIP) steel comprising 0.2C–4Al–1.2Mn–0.3Mo (wt%). The mechanical and microstructural characteristics that result from varied isothermal bainitic transformation (IBT) temperatures following inter-critical annealing at 820℃ for 10 min are thoroughly analyzed. The microstructure of the steels consisted of δ-ferrite, α-ferrite, bainitic ferrite, retained austenite (RA), and martensite, resulting in an optimum combination of the ultimate tensile strength (UTS) and total elongation (TE). The results of the investigation showed that IBT temperature had an effect on the stability of RA and the martensitic transition. Due to the increased mechanical stability of RA, the study revealed that the TRIP phenomenon was more prominent at lower IBT temperatures. Both tensile and yield strengths, as well as elongation, decreased as a consequence of the increase in IBT temperature. Maximum values of UTS, TE, and the product of these two properties (PSE) are attained (860 MPa, 41%, and 35260 MPa∙%, respectively) under optimal processing conditions (at 350℃ IBT temperature in 10 min).

Unleashing multi-scale mechanical enhancement in NiTi shape memory alloy via annular intra-laser deposition with homogenized Ti2Ni nanoprecipitates

Additive manufacturing (AM) of composition-sensitive NiTi shape memory alloys (SMAs) is hindered by uncontrollable non-equilibrium microstructures, leading to functional performance degradation and limitations in high-throughput net-shaping applications. To address these challenges, we propose a novel approach combining annular intra-laser directed energy deposition (AIL-DED) with a tailored gradient post-treatment process. This enables the fabrication of nanocomposite microstructures in NiTi SMAs with precise control over the homogenization of Ti2Ni nanoprecipitates. In-situ monitoring and characterization of thermal history, microstrain, and constitutional phases, were utilized to uncover the relationship between multi-scale structural features and mechanical responses. The interplay between laser reflectivity, energy input, and lattice thermal vibrations affects forming quality in AIL-DED. Dynamic temperature variations were studied before reaching thermal equilibrium, revealing insights into thermal and mechanical interactions during the process. These findings contribute to understanding challenges in fabricating high-quality NiTi SMAs. Examining phase transformation behavior and its correlation with processing parameters deepens understanding of microstructural evolution and provides insights for tailoring material properties. The stress relaxation and dislocation evacuation at elevated temperatures caused the expansion of lattice and interplanar spacing in the age-treated SMA's B2 matrix phase, exhibiting a stable two-step phase transformation behavior (B19′↔R↔B2). AIL-DED combined with two-stage heat treatment strategy demonstrated enhanced homogeneity of non-equilibrium microstructures, resulting in the formation of high-density, well-dispersed Ti2Ni nanoprecipitates, with a semi-coherent interface to B2 matrix. The combination of load-bearing strengthening through well-dispersed Ti2Ni nanoprecipitates and Orowan strengthening at the semi-coherent interface yielded simultaneous enhancements in nanohardness, ultimate compressive strength, compressive fracture strain, and deformation recovery, following the AIL-DED combined with two-stage heat treatment process. The fracture mechanism transitioned from a mixture of brittle-ductile behavior to predominantly ductile characteristics. This study provides valuable insights that advance additive manufacturing and enhance the functional performance of SMAs in critical applications.

Effect of two-stage thermal treatment on the reduction of quinoline-insoluble in Mesophase pitch

ABSTRACT Mesophase pitch (MP) is an important carbon material precursor with excellent physical performance and has a wide application in new energy utilization field. However, the current preparation process leads to a high quinoline-insoluble (QI) content in the MP, limiting its application. Here, we use two-stage thermal treatment to slow the degree of polycondensation during the formation of the MP. The two-stage thermal treatment can facilitate the formation of MP and limit the generation of QI. Moreover, the low content of polycyclic aromatic hydrocarbons (PAHs) in the liquid by-products indicates that the degree of thermal cracking of the feedstock becomes milder. The high content of cycloparaffins in gaseous by-products is due to the better polycondensation of the feedstock. Therefore, a wide area streamlined MP is prepared, which has a high mesophase content (96.8%), a low QI content (20.6%) and a good crystal structure (L c = 57.37 Å, N = 17.64, n = 99.53). At last, a possible mechanism of MP sample formation is discussed, which will provide an insight in the optimization of MP preparation process.

Two-Stage Treatment of Chronic Periprosthetic Knee Infections With the Use of Gentamicin-Articulated Spacers: Success Rate and Predictors of Failure at the Minimum Seven-Year Follow-Up.

The purpose of this study was to assess the survivorship rates of 2-stage treatment with gentamicin-impregnated polymethylmethacrylate articulated knee spacer in patients with chronic periprosthetic joint infection and to identify risk factors associated with failure. We conducted a retrospective study among 73 patients with chronic periprosthetic joint infection after primary total knee replacement with articulated polymethylmethacrylate gentamicin-impregnated spacers (Subiton, Medical Labs, Ind Argentina), performed in a single institution with a minimum follow-up of 7years. Clinical and functional assessment was performed with Knee Society Score and Western and Ontario McMaster Universities Osteoarthritis Index. A univariate and multivariate analysis was performed to identify the variables that influenced the success and failure rates. We included 73 patients. There were 53 (71.3%) monomicrobial, 11 (15%) polymicrobial, and 10 (13.7%) negative cultures infections. The success and failure rates were 90.5% (n= 66) and 9.5% (n= 7), respectively. Multivariate analysis identified that age (odds ratio= 1.77; P= .039), greater erythrocyte sedimentation rate values prior to the first stage (odds ratio= 1.04; P= .006), and polymicrobial infections (odds ratio= 7.32; P= .0003) were independent variables associated with failure. Two-stage revision with polymethylmethacrylate gentamicin-impregnated knee spacers is an effective strategy for the treatment of chronic periprosthetic joint infection after total knee arthroplasty. Age, higher erythrocyte sedimentation rate values prior first stage, and polymicrobial infections were independent risk factors for treatment failure.

The effect of the austenitisation temperaturefor the two-stage heat treatment of high-manganesesteels on its wear resistance under abrasiveconditions

Fine-grained high-manganese X120Mn12 grade steel was subjected to a two-stage heat treatment consisting oflong-term isothermal annealing at 510C, which was followed by resaturation in order to reduce the negativeeffect of the brittle carbide carbides of manganese cementite (Fe,Mn)3C. The objective of the experimentwas to elucidate the effects of distinct stages of heat treatment on the properties of high manganese steelwith regard to its resistance to abrasive wear. Supersaturation was performed for eleven different variationsof temperature values ranging from 600C to 1100C to verify its effect on the resistance to abrasion wearunder abrasion conditions. An increase in the supersaturation temperature results in the gradual coagulationand disintegration of the colonies of pearlite and needle-like carbides (Fe,Mn)3C formed during isothermalannealing. At the same time, as a result of the PSN (particle stimulated nucleation) process, the microstructureof austenite undergoes partial refinement, which ultimately increases the resistance to abrasive wear. As aresult of the final microstructural changes resulted in an increase in the resistance to abrasion of approximately6% compared to the initial state.